Your Brain Can't Keep Up!

Part 1 in the series The Brain, the Screen and the School

I recently listened to neuroscientist Sissela Nutley give a lecture. Nutley holds a PhD in cognitive neuroscience from Karolinska Institutet , serves as scientific lead for the school programme Det Syns Inte and is the author of Distraherad (Natur & Kultur, 2019/2022). She is one of the Swedish researchers who most clearly connects neuroscience with what is happening in our classrooms and our children’s bedrooms.

Much of what she said I recognised from before. But hearing her lay it out together, with fresh data, sharpened the picture. My concern was confirmed again. And my anger grew.

150 million years against seven years of app development

Nutley begins with the oldest parts of the brain. The limbic system, approximately 150 million years old, which governs our emotional drives: curiosity, reward-seeking, fear. These are structures that have helped us survive. They react with lightning speed, they are highly automated, and they have one single goal: to get us through the next second.

On top of that we have the prefrontal functions. They help us plan, think long-term and regulate impulses. They have existed in their current form for approximately 40,000 years. That sounds like a long time. But relative to the limbic system’s 150 million years, they are newcomers. And in conflict situations, they lose more often than we care to admit.

This is where it gets interesting, because the limbic system matures early in life. The prefrontal lobes do not fully mature until the ages of 20 to 25. So throughout childhood, and especially adolescence, children have a powerful accelerator system and a brake that is still under development.

Nutley describes this with a simple but apt observation. You can have a fantastic conversation with a 16-year-old. Reason through things carefully. Agree on sensible boundaries. And the next day it is as though the conversation never happened. Not because the teenager is stupid or unwilling. But because in the moment that counts, the frontal lobe cannot always take command over the limbic impulses.

I recognised this. Not only as a parent but as a former teacher. That conversation you thought had landed — only to find it had vanished in competition with everything else clamouring for a teenager’s attention.

“It’s a race to the bottom of the brain stem”

And this is where it gets truly unsettling.

Nutley refers to a phrase coined by Tristan Harris , former design ethicist at Google: “It’s a race to the bottom of the brain stem.” Tech companies are competing to reach as deep into the brain’s oldest structures as possible. Where we cannot steer by willpower. Where we act on instinct.

It is not an accident that TikTok captures a new user after approximately 260 videos, or 35 minutes. Internal documents that leaked via a lawsuit in Kentucky in 2024 show that this is a design objective. The algorithm detects that you pause for a second in the feed — sometimes simply because you react with discomfort — and immediately adapts what it shows you next.

The business model is simple. The longer you stay, the more ads you see, the more data you generate. Time is the product. And the tools used to capture that time are designed to trigger exactly those parts of the brain that we adults struggle enough with — and that children and young people have not yet developed the capacity to withstand.

It is one thing to know this intellectually. It is quite another to hear a neuroscientist lay it out with data and without equivocation.

Why the mobile phone ban on 1 July is right

On 1 July 2026, the national mobile phone ban comes into force in Swedish compulsory schools. Phones will be collected at the start of the school day and returned when pupils go home. Most schools already do this, but now it becomes law.

I have followed this question both as Second Deputy Chair of the Primary School Board in Örebro and with a background of ten years as an educational systems developer in upper secondary school, where I designed learning environments for pupils on the Media Programme. I think it is right. This is not about hostility to technology. I have built digital learning environments myself and know what technology can offer when used with care. But it is about rigging environments that give children’s brains a fair chance.

Nutley presents data from a Norwegian study of 477 schools that gradually introduced phone-free policies. The effects were clear: positive effects on girls’ grades, better mental health, reduced bullying. A large American study that Nutley referred to, involving 40,000 young people, showed the same pattern. Some grumbling in the first year, then positive wellbeing.

Swedish research using accelerometer measurements also shows that pupils simply move more at break times when the phones are gone. They go outside. They talk to each other. Someone might even skip rope, for all I know.

But — and this is important — the phone ban is not enough. Removing something creates a void. And as anyone who has worked in schools knows, voids are quickly filled by whatever is at hand. Schools must also offer something. Trusted adults at break times. Activities. Environments that make being outside actually enjoyable.

Adults who rig environments

Nutley often uses the word “rig”. Rig environments so that it becomes easier to end up in the behaviours that are good for us in the long run. It is the opposite of telling a 14-year-old “you should know better” when their frontal lobe is still under construction.

This applies in school. It applies at home. And it applies in politics.

As a school politician in Örebro I often think about this in terms of what we can actually decide and influence. The phone ban is one piece of the puzzle. But there are more: how we organise pupil health services, how we support parents, how we ensure that leisure activities offer alternatives to the screen.

We cannot change the fact that the limbic system is 150 million years old. But we can stop pretending that children should manage on their own against algorithms designed by the smartest engineers in the world to hack exactly that system.

This is not about being a luddite. It is about taking children’s brains seriously.

In the next part I look more closely at what Sissela Nutley’s sleep data shows, and why the phone in the bed may be the single most important question we should be discussing at parent evenings.